Re: [vserver] Undefined references to `__umoddi3' and `__udivdi3'

You are right, it doesn't need to be patched. I don't have a kernel handy,
but Google Code Search <http://www.google.com/codesearch/> shows me it was
in the main kernel branch in 2.6.24 and was in 2.6.25, so I assume this has
been permanently fixed in later versions. While searching I did find a
number of other places where fixes similar to this one have been applied to
the 2.4 and 2.6 kernels, so the information might be useful in the future.

Have fun,
D.

blaze your trail

--
redhat
http://feeds.feedburner.com/GeneralMusing
2009/11/1 Herbert Poetzl <herbert@13thfloor.at>
> On Sun, Nov 01, 2009 at 04:18:46AM +0000, Daniël W. Crompton wrote:
> > Sorry Herbert you are absolutely right.
>
> > From Gentoo Portage, 2.6.22-vs2.2.0.7-gentoo, using gcc
> > (Gentoo 4.3.2-r3 p1.6, pie-10.1.5) 4.3.2
>
> that kernel is 1.5 years old, and your gcc is pretty
> new, so it optimizes out the loop and uses a div/mod,
> which is not available to the kernel (lack of libgcc)
>
> I think the patch you mentioned should be fine, but
> I see no point in adding it to the 2.6.22.x branch ...
> (would require additional testing with older and newer
>  gcc as well as verification that it doesn't harm
>  anything)
>
> possible alternative solutions:
>
>  - get an older gcc, which is known to compile that
>   kernel fine (vanilla)
>
>  - get a newer kernel, preferably 2.6.31.x and use
>   that instead of the old 2.6.22.x branch
>
> best,
> Herbert
>
> > Ciao,
> > Daniel
>
> > blaze your trail
>
> > --
> > redhat
> >
> > http://feeds.feedburner.com/GeneralMusing
> >
> > 2009/10/31 Herbert Poetzl <herbert@13thfloor.at>
> >
> > > On Sat, Oct 31, 2009 at 07:04:33PM +0000, Daniël W. Crompton wrote:
> > > > Happy Halloween,
> > > >
> > > > I was getting a error (below) while compiling a new kernel, I found
> out
> > > that
> > > > a patch (also below) was required for linux/include/time.h as part of
> the
> > > > code is being optimized away losing the references.
> > > >
> > > > I check the vserver mailing list and didn't see any post about this
> > > issue,
> > > > so I am posting it here so we now have a record of it.
> > > >
> > > > Ciao,
> > > > Daniel
> > > >
> > > >
> > > > *ERROR:*
> > > > make bzImage
> > > > ...
> > > >   LD      .tmp_vmlinux1
> > > > kernel/built-in.o: In function `getnstimeofday':
> > > > (.text+0x22bdc): undefined reference to `__umoddi3'
> > > > kernel/built-in.o: In function `getnstimeofday':
> > > > (.text+0x22bfc): undefined reference to `__udivdi3'
> > > > kernel/built-in.o: In function `do_gettimeofday':
> > > > (.text+0x22d0e): undefined reference to `__udivdi3'
> > > > kernel/built-in.o: In function `do_gettimeofday':
> > > > (.text+0x22d2c): undefined reference to `__umoddi3'
> > > > kernel/built-in.o: In function `timekeeping_resume':
> > > > timekeeping.c:(.text+0x22fd4): undefined reference to `__umoddi3'
> > > > timekeeping.c:(.text+0x22ff4): undefined reference to `__udivdi3'
> > > > kernel/built-in.o: In function `update_wall_time':
> > > > (.text+0x23306): undefined reference to `__umoddi3'
> > > > kernel/built-in.o: In function `update_wall_time':
> > > > (.text+0x23326): undefined reference to `__udivdi3'
> > > > kernel/built-in.o: In function `update_wall_time':
> > > > (.text+0x23796): undefined reference to `__umoddi3'
> > > > kernel/built-in.o: In function `update_wall_time':
> > > > (.text+0x237b6): undefined reference to `__udivdi3'
> > > > make: *** [.tmp_vmlinux1] Error 1
> > >
> > > what kernel and Linux-VServer patch is that?
> > > and what compiler do you use?
> > >
> > > TIA,
> > > Herbert
> > >
> > > > *PATCH:*
> > > >
> > > > diff --git a/include/linux/time.h b/include/linux/time.h
> > > > index 2091a19..d32ef0a 100644
> > > > --- a/include/linux/time.h
> > > > +++ b/include/linux/time.h
> > > >
> > > > @@ -174,6 +174,10 @@ static inline void timespec_add_ns(struct
> > > > timespec *a, u64 ns)
> > > >  {
> > > >       ns += a->tv_nsec;
> > > >       while(unlikely(ns >= NSEC_PER_SEC)) {
> > > > +             /* The following asm() prevents the compiler from
> > > >
> > > > +              * optimising this loop into a modulo operation.  */
> > > > +             asm("" : "+r"(ns));
> > > > +
> > > >               ns -= NSEC_PER_SEC;
> > > >               a->tv_sec++;
> > > >       }
> > > >
> > > >
> > > >
> > > >
> > > > blaze your trail
> > > >
> > > > --
> > > > redhat
> > > >
> > > > http://feeds.feedburner.com/GeneralMusing
> > >
>